A 33-year-old employee sustained first-degree burns to her hands and arms, and a second employee, a 44-year-old woman, complained of burning in her eyes, Dunlap said. About 50 employees were evacuated.

A county bomb squad and agents from the federal Bureau of Alcohol, Tobacco and Firearms were investigating the explosion at Apex, which recently became a subsidiary of Home Depot but retained its management.

Also on Wednesday, Home Depot reported a bomb threat at its corporate headquarters in Vinings, just northwest of Atlanta. It was not known if the two incidents were related.

After the telephoned threat, Home Depot workers said they found a suspicious looking package in the mailroom, spokeswoman Jackie Tate said. The corporate headquarters, which employs about 4,000 workers, was evacuated and a police bomb squad was called to the scene.